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Infrared Camera (infrared + camera)
Selected AbstractsConstraints on the initial mass function of the first starsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2006Raffaella Schneider ABSTRACT Motivated by theoretical predictions that the first stars were predominantly very massive, we investigate the physics of the transition from an early epoch dominated by massive Pop III stars to a later epoch dominated by familiar low-mass Pop II/I stars by means of a numerically generated catalogue of dark matter haloes coupled with a self-consistent treatment of chemical and radiative feedback. Depending on the strength of the chemical feedback, Pop III stars can contribute a substantial fraction (several per cent) of the cosmic star formation activity even at moderate redshifts, z, 5. We find that the three z, 10 sources tentatively detected in Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Ultra Deep Fields (UDFs) should be powered by Pop III stars, if these are massive; however, this scenario fails to reproduce the derived Wilkinson Microwave Anisotropy Probe (WMAP) electron scattering optical depth. Instead, both the UDFs and WMAP constraints can be fulfilled if stars at any time form with a more standard, slightly top-heavy, Larson initial mass function. [source] Helicoverpa armigera (Hübner): can wheat stubble protect cotton plants against attack?AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2006Amanda J Cleary Abstract, When investigating strategies for Helicoverpa armigera (Hübner) control, it is important to understand oviposition behaviour. Cotton (Gossypium hirsutum) was sown into standing wheat (Triticum astivum L.) stubble in a closed arena to investigate the effect of stubble on H. armigera moth behaviour and oviposition. Infrared cameras were used to track moths and determine whether stubble acted as a physical barrier or provided camouflage to cotton plants, thereby reducing oviposition. Searching activity was observed to peak shortly before dawn (03:00 and 04:00 h) and remained high until just after dawn (4 h window). Moths spent more time resting on cotton plants than spiralling above them, and the least time flying across the arena. While female moths spent more time searching for cotton plants growing in wheat stubble, the difference in oviposition was not significant. As similar numbers of eggs were laid on cotton plants with stubble (3.5/plant SE ±0.87) and without stubble (2.5/plant SE ±0.91), wheat stubble does not appear to provide camouflage to cotton plants. There was no significant difference in the location of eggs deposited on cotton plants with and without stubble, although more eggs were laid on the tops of cotton leaves in wheat stubble. As the spatial and temporal distribution of eggs laid on the cotton plant is a crucial component of population stability, eggs laid on the upper side of leaves on cotton plants may be more prone to fatalities caused by environmental factors such as wind and rain. Therefore, although stubble did not influence the number of eggs laid, it did affect their distribution on the plant, which may result in increased mortality of eggs on cotton plants sown into standing wheat stubble. [source] The role of the medial caudate nucleus, but not the hippocampus, in a matching-to sample task for a motor responseEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2006Raymond P. Kesner Abstract A delayed-match-to-sample task was used to assess memory for motor responses in rats with control, hippocampus, or medial caudate nucleus (MCN) lesions. All testing was conducted on a cheeseboard maze in complete darkness using an infrared camera. A start box was positioned in the centre of the maze facing a randomly determined direction on each trial. On the sample phase, a phosphorescent object was randomly positioned to cover a baited food well in one of five equally spaced positions around the circumference of the maze forming a 180-degree arc 60 cm from the box. The rat had to displace the object to receive food and return to the start box. The box was then rotated to face a different direction. An identical baited phosphorescent object was placed in the same position relative to the start box. A second identical object was positioned to cover a different unbaited well. On the choice phase, the rat must remember the motor response made on the sample phase and make the same motor response on the choice phase to receive a reward. Hippocampus lesioned and control rats improved as a function of increased angle separation used to separate the correct object from the foil (45, 90, 135, and 180 degrees) and matched the performance of controls. However, rats with MCN lesions were impaired across all separations. Results suggest that the MCN, but not the hippocampus, supports working memory and/or a process aimed at reducing interference for motor response selection based on vector angle information. [source] Fatigue crack initiation detection by an infrared thermography methodFATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 1 2010D. WAGNER ABSTRACT In this paper, the study of the temperature variation during fatigue tests was carried out on different materials (steels and aluminium alloys). Tests were performed at ambient temperature using a piezoelectric fatigue system (20 kHz). The temperature field was measured on the surface of the specimen, by means of an infrared camera. Just at the beginning of the test, it was observed that the temperature increased, followed by a stabilization which corresponds to the balance between dissipated energy associated with microplasticity and the energy lost by convection and radiation at the specimen surface and by conduction inside the specimen. At the crack initiation, the surface temperature suddenly increases (whatever the localization of the initiation), which allows the determination of the number of cycles at the crack initiation and the number of cycles devoted to the fatigue crack propagation. In the gigacycle fatigue domain, more than 92% of the total life is devoted to the initiation of the crack. So, the study of the thermal dissipation during the test appears a promising method to improve the understanding of the damage and failure mechanism in fatigue and to determine the number of cycles at initiation. [source] Online temperature measurement and simultaneous diameter estimation of fibers by thermography of the spinline in the melt spinning processADVANCES IN POLYMER TECHNOLOGY, Issue 3 2004M. Golzar Abstract Online measurements of the temperature and the diameter of fibers in the melt spinning process of thermoplastics are discussed. The temperature and the diameter of fibers can be applied in many fields such as fiber formation modelling, cooling rate behavior (Nusselt number), and rheological investigations (apparent extensional viscosity) of polymers. The online measurements along the spinline were carried out with an infrared camera during the melt spinning process. Two different experiments were designed and carried out to find the correction factor, i.e., the emissivity. The results show that the emissivity correction factor depends on the polymer type and the fiber diameter. Usually the diameter of the fibers is measured by an instrument or by direct velocity measurements invoking the continuity equation. In this new approach the diameter is found directly by the evaluation of the measured temperature. Therefore only one apparatus, namely an infrared camera taking snapshots, is required to find the fiber diameter. The key of this method can be seen in the temperature difference between the fiber and the environment. A mathematical procedure was developed to estimate the diameter of the fiber from the distribution curve. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 176,185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20008 [source] Effect of temperature distribution and current crowding on the performance of lateral GaN-based light-emitting diodesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010Dongpyo Han Abstract Current crowding effect is detrimental for the performance of light-emitting diodes (LEDs), causing non-uniform light emission and local heat generation. In particular, heat generated by non-uniform current distribution can badly influence the performance of LED devices. In this paper, we examine the temperature distributions of lateral InGaN/GaN multiple-quantum-well LEDs in relation to current crowding, using both simulation and experimental results. Simulation results are obtained from a 3-dimensional electrical circuit model consisting of resistances and intrinsic diodes. Temperature and luminance distributions are investigated by images taken by an infrared camera and a charge-coupled-device camera, respectively. Finally, the internal quantum efficiency is taken for each device and compared. We show that the thermal property in the lateral LED is affected by the current crowding due to the local Joule heating nearby electrodes. Therefore, uniform current spreading is very important not only for uniform luminance distribution but also for good thermal property in the LED device. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Detecting sub-surface cracking in laminated membranes using infrared imagingPOLYMER COMPOSITES, Issue 6 2001Thomas J. Mackin This paper presents a new experimental method that utilizes the thermoelastic effect to detect sub-surface cracks in a laminated polymer membrane. A highly accurate infrared camera is used to measure the thermoelastic and dissipational heat signatures associated with bi-axial fatigue loading of membranes. Changes in these thermal signatures arise whenever cracks form in any layer of the laminate, including fully embedded layers, thereby providing a novel method for experimentally measuring the initiation and growth of damage in sub-surface layers. The proposed method is illustrated using a model 3-layer system of EVOH sandwiched between two polyurethane layers. Bi-axial fatigue loading was used to initiate cracking in the central EVOH layer without damaging the outer polyurethane layers. Cracking in the central layer resulted in a distinct thermal signature that was plainly visible using the proposed method. [source] An inverse estimation of initial temperature profile in a polymer processPOLYMER ENGINEERING & SCIENCE, Issue 1 2008Ali A. Ranjbar Since one of the most important parameter in polymer processing such as injection stretch blow molding is temperature distribution in the thickness direction, an inverse method has been applied to estimate this profile. This process comprises of four steps. In the first step the preform is injection molded, and in the second and third step it is stretched by a rod to its final length and then inflated and in the last step it is discharged from the mold. In such kind of polymer flows viscous dissipation plays a remarkable role in the evolution of temperature profile. Some theoretical temperature profile has been applied to confirm the validation of the inverse algorithm. Different solution techniques are applied in this article to the inverse problem under consideration, namely: the conjugate gradient and Levenberg,Marquardt method. After the preform is injection molded, which is the first step, it is removed from the mold, which corresponds to time t = 0. At this moment an infrared camera is used to record the surface temperature of the preform with a certain time step. With regard to variation of thermal properties with temperature, the inverse problem becomes nonlinear. These experimental data provided by the infrared camera are then used to estimate the temperature profile at the end of injection process before stretching and inflation took place. POLYM. ENG. SCI., 48:133,140, 2008. © 2007 Society of Plastics Engineers [source] Zerstörungsfreie Ortung von Fehlstellen und Inhomogenitäten in Bauteilen mit der Impuls-ThermografieBAUTECHNIK, Issue 10 2004Ralf Arndt Dipl.-Ing. Im Rahmen eines von der Deutschen Forschungsgemeinschaft geförderten Forschungsvorhabens wird von der Bundesanstalt für Materialforschung und -prüfung (BAM) und der Technischen Universität Berlin (TUB) die Anwendung der Impuls-Thermografie zur zerstörungsfreien Prüfung von Bauteilen und Bauwerken weiterentwickelt. Zu diesem Zweck werden Messungen zu verschiedenen baupraktischen Fragestellungen durchgeführt. Die Bauteiloberflächen werden mit einer Wärmequelle, die dem Prüfproblem angepaßt ist, erwärmt. Der daran anschließende Abkühlungsvorgang wird mit einer Infrarotkamera beobachtet und aufgenommen. Die anschließende Auswertung der gespeicherten Daten wird im Zeitbereich mittels numerischer Verfahren und im Frequenzbereich mittels Puls-Phasen-Thermografie durchgeführt. Die Puls-Phasen-Thermografie führt insbesondere zu einer praxisrelevanten Reduzierung des Störeinflusses von Oberflächeninhomogenitäten und ungleichmäßiger Erwärmung. Non-destructive detection of voids and inhomogeneities in building structures using impulse thermography. In the frame of a research project funded by the "Deutsche Forschungsgemeinschaft" the application of impulse thermography for the non-destructive testing of building components and buildings is further developed by the Federal Institute for Material Research and Testing (BAM) and the Technical University of Berlin (TUB). To this aim measurements to several practical problems of civil engineering were carried out. The inspected specimen is pulse heated according to the problem. The following cooling down process is recorded with an infrared camera. The transient behaviour is afterwards analysed by numerical methods in the time domain and by means of Pulse-Phase-Thermography in the frequency domain. Pulse-Phase-Thermography in particular reduces the influence of inhomogeneous surfaces and non-uniform heating on thermographic measurements. [source] Gas Hydrates in the Qilian Mountain Permafrost, Qinghai, Northwest ChinaACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 1 2010Youhai ZHU Abstract: Qilian Mountain permafrost, with area about 10×104 km2, locates in the north of Qinghai-Tibet plateau. It equips with perfect conditions and has great prospecting potential for gas hydrate. The Scientific Drilling Project of Gas Hydrate in Qilian Mountain permafrost, which locates in Juhugeng of Muri Coalfield, Tianjun County, Qinghai Province, has been implemented by China Geological Survey in 2008,2009. Four scientific drilling wells have been completed with a total footage of 2059.13 m. Samples of gas hydrate are collected separately from holes DK-1, DK-2 and DK-3. Gas hydrate is hosted under permafrost zone in the 133,396 m interval. The sample is white crystal and easily burning. Anomaly low temperature has been identified by the infrared camera. The gas hydrate-bearing cores strongly bubble in the water. Gas-bubble and water-drop are emitted from the hydrate-bearing cores and then characteristic of honeycombed structure is left The typical spectrum curve of gas hydrate is detected using Raman spectrometry. Furthermore, the logging profile also indicates high electrical resistivity and sonic velocity. Gas hydrate in Qilian Mountain is characterized by a thinner permafrost zone, shallower buried depth, more complex gas component and coal-bed methane origin etc. [source] Shoeing sound Warmblood horses with a rolled toe optimises hoof-unrollment and lowers peak loading during breakoverEQUINE VETERINARY JOURNAL, Issue 3 2006M. C. V. van Heel Summary Reasons for performing study: Overload injuries in sport horses commonly occur; shoeing techniques are believed to be important in prevention of these injuries, but there is a paucity of scientific information identifying the potential connection. Objectives: To test a horseshoe with a modified rolled toe designed to ease the process of breakover and decrease loading of lesion-prone structures of the distal limb. Methods: Twenty clinically sound Warmblood horses trotted over a track containing a pressure/force measuring system and 6 infrared cameras. The horses were measured with 2 types of shoes, standard flat shoes and shoes with a rolled toe. The shoeing procedure was randomised and horses had 2 days between measurements to adapt to the shoes. Results: Limb placement and timing characteristics, e.g. breakover duration, did not change significantly. There was an improvement in the ease of movement to roll over the toe in the shoes with a rolled toe, due mainly to a smoother hoof-unrollment pattern. The peak indicative moment decreased substantially at the onset of breakover in the shoe with the rolled toe. Conclusions: With a rolled toe the process of hoof-unrollment is smoother, which improves the coordination of this process, and lowers peak loading of the distal limb during breakover. Potential relevance: This study stresses the importance of proper shoeing in sound horses, showing that shoe modifications can optimise the loading characteristics of the distal limb and therefore might be a means to prevent sport horses from overload injuries. [source] The relation between skin temperature increase and sensory block height in spinal anaesthesia using infrared thermographyACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 9 2010F. G. A. M. Van HAREN Background and objectives: To evaluate the feasibility of determining the extent of sympathetic blockade by skin temperature measurement with infrared thermography and relate the cranial extent of the temperature increase to that of the sensory block after spinal anaesthesia. Methods: Before and 5, 10 and 20 min after the administration of spinal anaesthesia, skin temperatures were measured with infrared thermography at the dermatomes T2,L3, in 12 male patients scheduled for lower limb surgery. The most cephalad dermatome at which sensory blockade occurred was related to the dermatome at which the largest temperature jump (corrected for baseline temperature) occurred. Results: The baseline temperatures showed considerable variation across the dermatomes, being lower below T12 than at the thoracic dermatomes. The mean difference between the level of the cephalad skin temperature elevation front (mean 1.03 °C, SD 0.8 °C) and cranial sensory block height was 0.10 dermatomes (SD 1.16), correlation coefficient (0.88, P<0.001). Conclusion: The varying baseline temperatures across the trunk, the limited sympathetic block-induced increase in skin temperature at the trunk and the difficult control of influences from the surroundings partly obscured the extent of the skin temperature increase and its correlation to sensory block height. These factors have to be controlled to improve the use of infrared cameras as an easy bedside tool for predicting the cranial extent of (sympathetic blockade during) spinal anaesthesia. [source] A portable system for continuous monitoring of bird nests using digital video recordersJOURNAL OF FIELD ORNITHOLOGY, Issue 3 2007Andrew J. Pierce ABSTRACT A variety of photographic methods have been described for monitoring nest predation. All have limitations for studying active nests in remote situations, such as size, expense, volume of data recorded, and types of trigger mechanisms. We developed a digital video surveillance system using infrared cameras to monitor predation at bird nests. The main advantage of this system over other video recorders is the small size of the recorder that can run continuously at 29 frames/s for more than 3 days. The recorder's built-in monitor makes it more transportable and allows for easy setup. Digital data is compact, can be reviewed quickly, and requires less physical storage space than videotapes. We recorded nest predation by mammals, birds, and snakes as well as egg and nestling losses not caused by predation. System failure rates were low and the total cost was comparable to ($700 US) video cassette recorders that are often used to monitor nests. SINOPSIS Se han descrito una gran variedad de métodos fotográficos para monitorear la depredación de nidos. Todos los métodos tienen limitaciones para estudiar nidos activos a distancia, como su tamaño, costo, volumen de los datos grabados y mecanismos para activar el equipo. Desarrollamos un sistema digital de vigilancia, utilizando cámaras infrarrojas para monitorear la depredación de nidos. La ventaja principal de este equipo sobre otros similares es el tamaño de la grabadora, la cual puede funcionar continuamente a 29 cuadros/s por más de tres días. El monitor integrado a la cámara hace que el equipo que sea más fácil de transportar y permite que se pueda montar con facilidad. Los datos digitales son compactos, se pueden revisar rápidamente, y requieren menos espacio de almacenaje que las cintas de video convencionales. Grabamos depredación de nidos por mamíferos, aves y culebras al igual que la pérdida de huevos y pichones por otras causas. La tasa de malfuncionamiento fue baja y el costo del equipo ($700 US) es comparable a otros equipos de videograbación a cassette que se utilizan frecuentemente para monitorear nidos. [source] Kinematic analysis of the pelvic limbs of healthy dogs during stair and decline slope walkingJOURNAL OF SMALL ANIMAL PRACTICE, Issue 8 2010R. P. Millard Objectives: To evaluate range of motion (ROM) of the pelvic limb in healthy dogs descending stairs compared with decline slope walking. Methods: Reflective spheres were placed on the skin over the joints of the right pelvic limb of seven adult, hound-type dogs with no clinical signs of orthopaedic or neurologic disease. Five trials of stair and ramp descent of each dog were recorded using four 60 Hz digital infrared cameras. Two-dimensional kinematic data were collected as dogs walked down stairs and on a continuous decline of equivalent slope. Maximum and minimum joint angles and ROM were calculated for the coxofemoral, femorotibial and tibiotarsal joints. Results: Stair descent resulted in significantly greater femorotibial flexion and tibiotarsal flexion and extension compared with continuous slope descent. Significantly greater ROM was achieved in the coxofemoral, femorotibial and tibiotarsal joints during stair descent. Clinical Significance: Compared with a continuous slope, stair descent achieves greater ROM in the pelvic limbs of dogs. Stair descent may be a useful therapeutic exercise to improve ROM in dogs with musculoskeletal disease of the pelvic limb, and ramp descent may be easier for dogs with limited motion of pelvic limb joints. [source] | |||||||||||||||||||